Honestly, the work I have done using SNMP...don't waste too much time.
To see what I mean, get a hold of the actual NetApp MIB file. Then do an SNMPwalk. You will find out very quickly the snmpwalk does not get all the supposedly available OIDs.
A lot of the OIDs worked under 7-mode and likley still work with 7-mode. Since the cluster is no longer a single node, many of those objects did not translate well.
Hope that helps a little.
ONTAP does a very good job with SNMP alerting (pushing) but I found the let of getting info through SNMP less than steller.